1. Field of the Invention
The instant disclosure relates to a solid-state electrolytic capacitor; in particular, to a solid-state electrolytic capacitor with improved metallic anode, and to a method for manufacturing the same.
2. Description of Related Art
The capacitor is an indispensable element in many electronic products. Various applications of capacitors include home appliances, computer motherboards and peripherals, power supplies, communication products and automobiles. The capacitors such as solid electrolytic capacitors are mainly used to provide filtering, bypassing, rectifying, coupling, blocking or transforming function. With the rapid advancement of semiconductor processing technology, packaged electronic products follows the trend of miniaturization, high electrical performance, multi-function, high reliability, and RoHS Compliance. The wet electrolytic capacitor cannot accommodate the requirements of the electronic products, thus, the solid state electrolytic capacitor is developed.
There are many different types of substrates that can be used for the solid-state electrolytic capacitor. Currently, aluminum and tantalum are the most commonly used materials for solid-state electrolytic capacitors. To increase capacitance, a plurality of solid-state electrolytic capacitors is laminated together in parallel to a form capacitor unit. Thus, a higher capacitance can be obtained, in which total capacitance is the sum of all values from all capacitor units.
Specifically, when stacking the capacitor units in a packaging process, two anode portions of the adjacent capacitor units are welded to each other. However, due to the thick anode portion of each capacitor unit almost always result in low welding quality and low welding success rate. Further, the maximum number of the stacked capacitor units is limited by the thick anode portion of each capacitor unit.
Moreover, in the welding process, molten aluminum can be readily produced and splattered when the thick anode portions of the capacitor units grinded against each other. However, the molten aluminum may occupy only portions of empty space inside the package body after solidification. When the solidifying aluminum is melted twice in a solder reflow process, voids that are form inside the package body can decrease airtightness. Thus, moisture can enter the package body that may affect electric properties of the capacitor units.